In the 1920s, a railroad man named Big Bob Gibson came up with a mayo-based barbecue sauce for chicken. One hundred years later, there's a reason people still love it.

Rare is the barbecue sauce that’s synonymous with just one guy. Most are associated with whole states—think South Carolina—or at least respectably sized cities, like Memphis. And rare is the barbecue sauce whose base is mayonnaise, rather than tomato, vinegar, or mustard. But in Alabama, they do things differently. Or at least Big Bob Gibson did.

Gibson was the mind behind the now beloved north Alabama sauce, which consists of mayo thinned with apple cider vinegar and lemon juice and punched up with black pepper. Where you stand on it will involve where you stand on mayo in general, but trust: the cool tang of Alabama white sauce has never harmed a grilled chicken leg. Later adherents have introduced slight modifications, adding cayenne pepper, horseradish, or sugar (or, in fancier quarters, sambal oelek and Aleppo pepper). The original recipe is still served at Big Bob Gibson BBQ, which maintains two locations in Decatur, Alabama. (I ate at one earlier this year and will happily vouch for it.)

In the 1920s, Gibson (six foot three, over 300 pounds: he earned the nickname) was a worker on the Louisville and Nashville Railroad—the L&N. He started making barbecue on the weekends: first for family members, then for friends. He dug the pit, he made a table out of oak planks nailed to a tree in his backyard. He cooked pulled-pork shoulders and whole chickens. His operation grew.

But Gibson had a dilemma, explains Big Bob's current pitmaster, Chris Lilly. He had put an eastern North Carolina–style vinegar sauce on his pork, but needed something to keep the moisture in his chicken, which cooked over the course of three hours. He found it: mayo. Gibson’s white sauce gave the meat a “peppery, vinegary flavor,” Lilly says, while keeping it from drying out. The Carolina and the white were the two sauces Gibson had on hand when he opened his original restaurant in 1925.

Other barbecue styles crisscross the state. “We’re caught between the Carolinas and Memphis and you have influence from both areas,” Lilly says. “I like to think of Alabama as the best of both worlds.” Gibson added something new and durable to the mix. People cycled in and out of his kitchen and then opened their own restaurants. Word spread. Big Bob Gibson’s barbecue sauce became northern Alabama’s.

“Everybody’s given their nod to Big Bob Gibson,” Lilly says, pointing out that you can find variations of his white sauce nowadays everywhere from the Publican, in Chicago, to New York’s Blue Smoke. It’s probably on surer footing there than it is in North Carolina, where recently a local newspaper used the word "invades" to describe what the Alabama sauce is doing at local barbecue shacks. Alabama may be ecumenical when it comes to its barbecue, but North Carolina is somewhat warier.

The point of Big Bob’s barbecue sauce, of course, is that it’s dead easy to make. It requires no restaurant at all, and only the barest recipe. Don't ask what you do with it—ask what you can't do with it. The answer is not much. Marinate chicken in the sauce; baste your bird with it while you're grilling. (At Big Bob Gibson, Lilly says, they dunk every chicken that comes off the smoker into a vat of the stuff.) And serve it on the table, too, to explore further possibilities. Lilly says it's good on chips, pork, wings, even salad. Why not? You never know what's going to catch on.